Socket adapter



Dec. 25, 1962 J. RABINOW SOCKET ADAPTER Filed Feb. 1, 1962 I NVEN TOR. Jacob Rab/now A T TORNEYJ United States Patent Ofiiice 3,070,767 Patented Dec. 25, 1962 SOCKET ADAPTER I g Jacob Rabinow, Takoma Park, Md., assignor to Rabmow Engineering Co., Inc., Rockville, Md.

Filed Feb. 1, 1962, Ser. No. 170,601 Claims. (Cl. 338-70) This invention relates to voltage reducing devices, and particularly to devices to prolong the life of electric lamps.

The life of ordinary electric lamps is quite short. electric lamps are not expensive, there appears to be no great effort directed towarl improving their useful life. Possibly, there are other reasons why electric lamps are not constructed of better quality but these are not pertinent here. The fact is that the life of electric lamps could be prolonged to avoid the bother of having to replace lamps when they burn out. Replacement of electric lamps is particularly bothersome when they are located in comparatively inaccessible places. It is even more of a bother to replace an electric lamp when to do so, for instance, requires that a fixture be partially disassembled. Ordinary ceiling fixtures are one example, especially if they are flush mounted. I

There are at least two ways to prolong the life of electric lamps, without improving the lamps themselves. One is to reduce the initial surge when a cold electric lamp is energized. Lamps often burn out at the instant that they are turned on. Another way to prolong the life of an electric lamp is to operate it below the rated voltage of the lamp. When doing this the illumination is reduced, but this presents no problem since one can use, for example, a 75 watt lamp in a place where one would ordinarily use a 60 watt lamp.

There have been prior methods of increasing the life of electric lamps. lamps are very high and in stadiums Where lights are used for night-time activities, the power is gradually increased so that there is no sudden surge. Then, when the lamps are heated, full power is applied. In addition, electric lamp intensity controls using resistors are very common. Most automobiles have intensity controls for the lamps which illuminate the instrument panels thereof. US. Patents Numbers 1,750,740 and 2,721,917 disclose intensity regulators for electric lamps which permit the electric lamps to operate at a voltage below the lamp-rated voltage. The devices disclosed in the above patents, as all other prior devices for the same purpose of which I am aware, suffer from the same drawback. They are complex and expensive for so simple a task. Their com plexity makes them questionably practical from a commercial standpoint.

The main object of my invention is to provide a simple, practical, and inexpensive voltage reducing adapter for a lamp, which also reduces initial surge and the voltage level at which the lamp operates, thereby prolonging the life of the lamp.

I emphasize the simplicity and practicability of my invention. To be commercially acceptable the voltage-re ducer adapter must be inexpensive, for example, it must cost approximately the same or less than a light bulb. Secondly, it must be safe, easy to use, and must occupy a very small space. The illustrated embodiment of my invention fulfills these requirements and yet, will achieve its objective of prolonging the life of electric lamps.

Other objects and features of importance will become apparent in following the description of the illustrated form of the invention.

FIGURE 1 is a partially elevational and partially sectional exploded view showing a conventional electric lamp, a conventional socket, and my adapter interposed therebetween.

Since For instance, in theaters where the FIGURE 2 is an end view or my adapter as it would appear along the line 2-2 of FIGURE 1.

The accompanying drawing shows a conventional electrical outlet as socket 10, which diagrammatically represents any kind of standard socket as would be used in a ceiling fixture, an outdoor sign, a table or floor lamp, etc. Electric lamp 12 is also conventional and as such, is provided with a threaded connector 14 at one end which would ordinarily fit into socket 10 with the center contact of the connector 14 engaging the center contact (not shown) of socket 10.

My adapter is made of a single piece, metal shell 16 having a first section 18 and a second section 20 coaxial therewith. Section 20 has a mouth 22 at one end defined by a cylindrical skirt which fits against (or partially around) the glass part of electric lamp 12 when the electric lamp is screwed fully into the adapter. Inasmuch as connector 14 must be threaded into the threads of section 20, the inside diameter of section 20 is of a size so that this section will accept and retain the connector of the electric lamp. For protective purposes section 20 has an outer coating 24 of insulating material, for instance a synthetic resin film, a ceramic wash, or the equivalent. Coating 24 is preferably (but not necessarily) bonded or otherwise adhered to the outer surface of section 20 of shell 16.

Section 18 of shell 16 must fit into and engage the shell (not shown) of socket 10. Therefore the outside diameter of section 18 is suitably dimensioned for this purpose, and it has screw threads so that the adapter may be threaded into socket 10 either before'or after the electric lamp 12 is engaged by section 20.

An electrically insulating base 26 extends transversely across the shell and is attached to one end of section 18, e.g. by crimping as at 27. The base can be made of ceramic, Bakelite, glass (as the base of connector 14) or the like. An axial projection, for instance, short post 28, forms a part of base- 26 and extends inwardly of shell 16. Post 28 serves several purposes, one of which is to support contact 30 against which the center contact of the electric lamp bears. As shown, contact 30 is a shallow cup which is pressed on or otherwise attached to post 28. If desired, the center part of contact 30 can be struck up to form a resilient contact such as shown in U.S. Patent No. 1,750,740 or as found in most conventional sockets 10. The outer center contact 32 is secured to the outer surface of base 26, and contact 32 may be of any configuration such as a shallow cup (shown) which is pressed in place, or a small metal soldering tab (not shown) which is partially embedded in the base. Resistor 34 is preferably a resistance wire which extends through a passage in base 26 and has one end crimped under or soldered to contact 32. The other end of the resistance wire is wrapped around post 28 and is secured to the inner contact 30 by suitable means such as soldering.

In use, the adapter is screwed into socket 10 and the lamp is screwed into the adapter. The electrical circuit for the filament of lamp 12 is established through shell 16, the threaded part of connector 14, the lamp filament, and then through the center contact of the lamp and contact 30, the resistor 34 and contact 32. When the adapter is used for a brief period, the resistor will produce heat. The heat will not be nearly so great as that produced by the electric lamp. The heat of the resistor will be dissipated through shell 16, it being noted that the insulated part of the shell is on the exterior of socket 10 where it may be cooled by ambient air. Accordingly, the adapter inherently functions as a heat sink for the heat of the resistor. When the light bulb 12 is operating at a reduced voltage, the heat generated by the bulb itself will be somewhat less than if the bulb operated at full intensity and therefore the total heat of the combined adapter and bulb 3 is slightly lower than that of the bulb used without the adapter.

It is understood that various changes, modifications and alterations may be made without departing from the protection of the following claims.

I claim:

1. A voltage reducing adapter for a lamp socket containing threads, said adapter comprising a single-piece conductive shell having a first section and a second section, said first section having a thread and being of an outside diameter to fit into said socket, said second section having a lamp-connector receiving thread and being of an internal diameter to receive a lamp connector, an insulating base attached to and closing one end of said first section, a contact rigidly and immovably fixed on the exterior of said base to engage the center contact of a socket, an insulating member rigid with said base and extending axially and inwardly of said first section, a second contact immovably fixed on the inner end of said member located within said first section to be engaged by the center contact of a lamp connector, and a resistor connected to said contacts so that when a lamp is screwed into said adapter and the adapter is screwed into a socket the resistor is in series with the lamp filament to reduce surges and also the voltage level at which the lamp operates.

2. The adapter of claim 1 wherein said first section has an insulating coating covering the exposed surface there of, and a skirt at one end of said second section to assure that the entire lamp base is received by said second section.

3. The adapter of claim 2 wherein said insulating member forms a seat and support for said second contact and also forms a support for said resistor.

4. A voltage reducing adapter for an electric socket containing threads, to prolong the life of an electric lamp by reducing electrical surge and the voltage level at which the lamp operates, said adapter comprising a single piece conductive shell having first and second axially aligned joined sections with the first section having a slightly smaller diameter than the second section, said sections having means to engage the threads of the electric socket and means to engage and hold the electric lamp respectively, a transverse insulating base joined to and transversely closing one end of said first section, a center contact rigidly and immovably fixed on the outer surface of said base and adapted to engage the center contact of the electric socket, a separate contact contained entirely within said first section and adapted to be engaged by the center contact of the lamp, a resistive wire, said base having a passageway through which said wire extends, said wire secured at its ends to the contacts of said adapter, and means to serve the dual purpose of supporting said separate contact and providing a support for a part of said wire, said dual purpose means comprising an insulating post fixed immovably to said base and extending axially within said base and having an end terminating short of the juncture of said first and second sections, and said separate contact attached to the end of said post thereby positioning the separate contact inwardly of said first section and on the longitudinal axis thereof.

5. The adapter of claim 4 and a mouth portion at the outer end of said second section which extends beyond said lamp engaging and holding means, and the location of said separate contact inwardly of said first section together with said mouth portion allowing the base of a conventional lamp to be received completely within the adapter and at such position that a portion of the lamp base is within the electric socket when the adapter is screwed into the socket.

References Cited in the file of this patent UNITED STATES PATENTS 1,310,696 Gardner July 22, 1919 2,721,917 Duerkob Oct. 25, 1955 

